using java dom to update file

**newbieal** · 10-09-2008, 06:51 PM

I've the following code and this html file. I'm trying to locate the <head> tag and add text in between it, however it isn't working. Could someone please take a look at my code and tell me what is missing? Thanks.

<xml version="1.0" encoding="UTF-8"?/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html"/>
<meta http-equiv="Content-Style-Type" content="text/css"/>
<title>a title</title>
</head>
<body>
<p>some text</p>
</body>
</html>

Java Code:

ocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            try
            {
                DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.parse(new File("test.html"));
            
        
        String newinfo = "text to be added";
 
         Element root = doc.getDocumentElement();
            NodeList rootlist = root.getChildNodes();
            
            for(int i=0; i<rootlist.getLength(); i++) 
            {
                Element head = (Element)rootlist.item(i);
                 NodeList namelist = head.getChildNodes();
                Text headtext = (Text)namelist.item(0);
                String oldname = headtext.getData();
                if(oldname.equals(newinfo)) 
                {
                    Element head2 = (Element)namelist.item(1);
                    NodeList namelist2 = head.getChildNodes();
                    Text headtext2 = (Text)namelist.item(0);
                    headtext.setData(newinfo);
                }
            }
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }

**Norm** · 10-09-2008, 07:44 PM

If you'll post code that compiles and executes, it'd be easier to test.

Also show the type of data you want to add. Is it HTML with special chars or just text?

**newbieal** · 10-09-2008, 07:58 PM

It is just text that should be added between the <head> tags. i'll keep trying to work on the code to make it compile but in the meanwhile any ideas why it isn't would be greatly appreciated.

**newbieal** · 10-09-2008, 09:10 PM

This is what I have so far, it compiles but does not accomplish what I need it to:

Java Code:

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	    try
	    {
		DocumentBuilder db = dbf.newDocumentBuilder();
	    Document doc = db.parse(new File("testing.html"));
	    String newinfo = "text to be added";

		Element root = doc.getDocumentElement();
	    NodeList rootlist = root.getChildNodes();
	    
	   Node current = null;
	   int count = rootlist.getLength();
	   for (int i = 0; i < count; i++)
	   {
		   current = rootlist.item(i);
		   if(current.getNodeType() == Node.ELEMENT_NODE)
		   {
			   Element element = (Element)current;
			   NodeList children = element.getChildNodes();
               if(element.getTagName().equalsIgnoreCase("head"))
			   {
				   Text headtext = (Text)children.item(0);
                   headtext.setData(newinfo);

			   }
			   
		   }
		   System.out.println(doc.getDocumentElement());
		   
	   }
	    }
	    catch (Exception e)
	    {
	    	e.printStackTrace();
	    }

**Norm** · 10-09-2008, 11:15 PM

If you'll post code that compiles and executes, it'd be easier to test.

That would include everything from import to ending }

it compiles

You have a better compiler than mine then.

**newbieal** · 10-10-2008, 07:50 PM

Java Code:

import java.io.File;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import com.sun.org.apache.xml.internal.serialize.XMLSerializer;


// using DOM
public class testingWriteToHTML {
	
	public static void main(String[] args) {

		
	    try
	    {
	    	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			dbf.setValidating(false);
			dbf.setNamespaceAware(false);
			dbf.setExpandEntityReferences(false);
			
	    	DocumentBuilder db = dbf.newDocumentBuilder ( );
	    	
	        Document doc = db.parse ( new File ( "test2.html" ) );
	   
	        String newinfo = "some text";
	   
	        Element root = doc.getDocumentElement ( );
	        // NodeList list = doc.getElementsByTagName ( "head" );
	        System.out.println ( root.getNodeName ( ) );
	        NodeList list = root.getChildNodes ( );
	        StringBuffer sb = new StringBuffer();
	         for ( int i = 0; i < list.getLength ( ); i++ ) 
	        {
	          if ( list.item ( i ).getNodeName ( ).equals ( "head" ) ) 
	          {
	        	  list.item ( i ).setTextContent ( newinfo );
	            
	          }
	        }
	        XMLSerializer serializer = new XMLSerializer ( );
	        serializer.setOutputCharStream ( new java.io.FileWriter ( "test2.html" ) );
	        serializer.serialize ( doc );

	    }
	    catch (Exception e)
	    {
	    	e.printStackTrace();
	    }

	}
}

**Norm** · 10-10-2008, 11:16 PM

I'm not sure that this is the way to go. Your app is supposed to insert some text/HTML between the <HEAD> and </HEAD> tags.
XML is much more precise/regulated than HTML. I would think you'd find HTML pages that would fail the XML parsing.

I'd vote for doing the scanning your self with indexOf() etc to find the <HEAD> tag and add your stuff and then copy the rest of the HTML page to output.

Comment on your code:
Don't use the same name for the input and output files.
For testing add a couple of String definitions at the head of the code:
final static String inFile = "test2In.html"; // Input file
final static String outfile = "test2Out.html"; // output file

It makes it easier to see what files are involved and to change them during your testing.